The invention relates generally to the field of blood pumps, and particularly continuous flow pumps of rotary design suitable for permanent implantation in humans, for use as chronic ventricular assist devices.
Thousands of heart patients who suffer from severe left ventricular heart failure could benefit from cardiac transplantation. However, owing to a shortage of donor hearts, most of these patients face a foreshortened life span characterized by frequent hospitalizations, severe physical disability, and death from congestive failure or cardiogenic shock. With the use of an effective left ventricular assist device on a chronic basis, many of these patients could be returned to prolonged and productive lives.
Such a left ventricular assist device is particularly shown in my prior copending application Ser. Nos. 08/603,536 and 08/910,375, which disclose pumps of rotary, continuous flow design rather than of a pulsatile flow design. The disclosed rotary blood pumps solve numerous clinical problems and have significant advantages for use as a left ventricular assist device, eliminating the necessity for a drive shaft seal and having axial thrust bearings which are regularly washed by fresh blood flow to prevent thrombosis from occurring.
However, it would be desirable to increase the blood flow across the end of the rotor of such rotary pumps, and rotary pumps of other designs, to further reduce the possibilities of clotting where low blood flow occurs at stagnation points such as areas of the pump rotor end near the axis of rotation.